Rotary compressor

ABSTRACT

A rotary compressor including a case defining an external appearance of the compressor. A compressing device is arranged inside the case, and a lower cap is fixed to a lower end of the case. The rotary compressor further includes a weld zone to fix the compressing device and lower cap to each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.2009-0000712, filed on Jan. 6, 2009 in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments of the present invention relate to a rotary compressor, acompressing device of which is fixedly welded inside a case via animproved configuration.

2. Description of the Related Art

In a general rotary compressor, an eccentric part and a roller arecoupled to a rotating shaft that is rotated via electromagneticinteraction between a stator and a rotor. As the eccentric part androller are eccentrically rotated in a compression chamber defined in acylinder, compression of refrigerant suctioned into the compressionchamber is accomplished. A vane is supported by a vane spring in thecompression chamber while being in contact with a surface of the roller,the vane dividing the compression chamber into a low-pressure chamberfor suction of refrigerant and a high-pressure chamber for discharge ofcompressed refrigerant. Such a rotary compressor includes a caseprovided with a refrigerant suction pipe and a refrigerant dischargepipe, a drive device to generate rotating force, and a compressingdevice to perform suction and compression of refrigerant.

The drive device includes a stator, a rotor, and a rotating shaftcoupled to the rotor and adapted to be rotated along with the rotor. Theeccentric part and roller are eccentrically coupled to one end of therotating shaft thus performing eccentric rotation via rotation of therotating shaft.

The compressing device includes the compression chamber in which theeccentric rotation of the eccentric part and roller is performed, thecylinder defining the compression chamber, an upper bearing and a lowerflange coupled respectively to upper and lower ends of the cylinder tohermetically seal the cylinder, and the vane dividing the compressionchamber into the high pressure chamber and the low pressure chamber, thevane being arranged in contact with an outer periphery of the roller andadapted to perform vertical sliding motion based on the eccentricrotation of the roller. The vane is supported by the vane spring in avane slot defined in one side of the cylinder.

A region of the case in contact with the cylinder is perforated with aplurality of through-holes, and each of the through-holes is formed witha weld zone to integrally couple the cylinder to the case by welding.

In the above-described rotary compressor, to fix the cylinder inside thecase, the plurality of through-holes may be perforated in the case andalso, an edge of each through-hole may be welded to the cylinder in aradial direction of the case. This may cause the case to be thermallydeformed by heat generated during welding, or the cylinder and the upperbearing to be deformed upon receiving the heat transmitted from thecase. In addition, welding the edge of the through-hole to the cylinderin the radial direction of the case causes distortion of a gap betweenthe stator and the rotor, resulting in excessive drive load of thecompressing device and deteriorating compression efficiency and use lifethereof.

SUMMARY

Therefore, it is an aspect of the present invention to provide a rotarycompressor, a compressing device of which may be fixed inside a casewith a minimized possibility of thermal deformation of a cylinder and anupper bearing, resulting in enhanced efficiency of the compressingdevice.

Additional aspects of the invention will be set forth in part in thedescription which follows and, in part, will be apparent from thedescription, or may be learned by practice of the invention.

In accordance with one aspect, a rotary compressor includes a casedefining an external appearance of the compressor, a compressing devicearranged inside the case, a lower cap fixed to a lower end of the case,and a weld zone to fix the compressing device and lower cap to eachother.

The weld zone may be formed by at least one reinforcing protrusionextending from the compressing device to the lower cap by apredetermined length.

The weld zone may be formed by at least one supporting protrusionprotruding from the lower cap to the compressing device by apredetermined length.

The compressing device may include a cylinder defining a compressionchamber for compression of refrigerant gas, and a lower bearing tosupport the cylinder from the lower side of the cylinder, and the weldzone may be formed in a boundary region between the reinforcingprotrusion axially provided at the lower bearing and a through-holeperforated in the lower cap.

The compressing device may include a cylinder defining a compressionchamber for compression of refrigerant gas, and a lower bearing tosupport the cylinder from the lower side of the cylinder, and the weldzone may be formed in a boundary region between a through-holeperforated in the supporting protrusion and the lower bearing.

The reinforcing protrusion may be provided at a peripheral position of alower bearing to come into close contact with a bottom surface of thelower cap when the lower cap is fixed to the case.

The supporting protrusion may be provided at a peripheral position ofthe lower cap to come into close contact with a lower bearing when thelower cap is fixed to the case.

The compressing device may further include an upper bearing to supportthe cylinder from the upper side of the cylinder.

The rotary compressor may further include a stator fixed to the case, arotor rotatably supported inside the stator, and a rotating shaftpress-fitted in the rotor.

In accordance with another aspect of the invention, a rotary compressorincludes a case, a cylinder arranged inside the case, a lower bearingclosely coupled to a lower end of the cylinder, and a lower cap fixedlywelded to the lower bearing for fixing the cylinder in an axialdirection.

At least one protrusion may be provided between the lower bearing andthe lower cap, to fixedly weld the lower bearing to the lower cap.

The protrusion may be integrally formed with any one of the lowerbearing and the lower cap.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent andmore readily appreciated from the following description of theembodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a sectional view illustrating a rotary compressor according toan embodiment of the present invention;

FIG. 2 is an exploded partial sectional view of the rotary compressorshown in FIG. 1;

FIG. 3 is a sectional view illustrating a compressing device and a lowercap of the rotary compressor according to the embodiment;

FIG. 4 is an enlarged perspective view of a lower bearing and the lowercap according to the embodiment;

FIG. 5 is a sectional view illustrating a rotary compressor according toanother embodiment; and

FIG. 6 is an enlarged perspective view illustrating a lower cap of therotary compressor shown in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout.

FIG. 1 is a sectional view illustrating a rotary compressor according toan embodiment, and FIG. 2 is an exploded partial sectional view of therotary compressor shown in FIG. 1.

As shown in FIGS. 1 and 2, a rotary compressor 10 according to theembodiment includes a case 100 defining an external appearance of thecompressor, a drive device 200 to generate drive force, and acompressing device 300 to compress refrigerant gas upon receiving thedrive force of the drive device 200. Both the drive device 200 and thecompressing device 300 are arranged inside the cylindrical case 100.

The case 100 includes a cylindrical case body 110 in which the drivedevice 200 and the compressing device 300 are mounted, an upper cap 120,a part of which is fixedly inserted into an upper end opening of thecase body 110, and a lower cap 130, a part of which is fixedly insertedinto a lower end opening of the case body 110.

The upper cap 120 is subjected to welding in a peripheral directionthereof so as to be coupled to an upper end of the case 100, and thelower cap 130 is subjected to welding in a peripheral direction thereofso as to be coupled to a lower end of the case 100. More particularly,the welding of the upper or lower cap is performed in a peripheraldirection such that a fixing weld zone 140 is created in a boundaryregion between the end of the case 100 and the cap.

A suction pipe 160 is connected to one side of a lower part of the case100, through which refrigerant gas is fed from an accumulator 150 to thecompressing device 300, the accumulator 150 functioning to filterliquid-phase refrigerant. Also, a discharge pipe 170 is connected to anupper part of the case 100, through which the refrigerant gas compressedin the compressing device 300 is discharged. An oil storage space 180 isprovided in a bottom region of the case 100, in which a predeterminedamount of oil is stored for lubrication and cooling of any frictionalmember.

The drive device 200 includes a stator 210 fixed to the case 100, arotor 220 rotatably supported inside the stator 210, and a rotatingshaft 230 press-fitted in the rotor 220. With this configuration, ifpower is applied to the stator 210, the rotor 220 is rotated byelectromagnetic force and simultaneously, the rotating shaft 230integrally press-fitted in the rotor 220 transmits a rotating force ofthe rotor 220 to the compressing device 300.

The compressing device 300 includes an eccentric part 310 formed near alower end of the rotating shaft 230, a roller 320 fitted around theeccentric part 310, a cylinder 330 defining a compression chamber 360 inwhich the roller 320 is received, and an upper bearing 340 and a lowerbearing 350 coupled respectively to an upper end and a lower end of thecylinder 330 and adapted to hermetically seal the compression chamber360 while supporting the rotating shaft 230.

The cylinder 300 and the upper and lower bearings 340 and 350 have boltfastening holes 300 b. As fastening bolts 300 a are fastened through thebolt fastening holes 300 b, the upper and lower bearings 340 and 350 arebrought into close contact with upper and lower surfaces of the cylinder330, thereby hermetically sealing the compression chamber 360.

The cylinder 330 is provided at one side thereof with a suction port370, which is connected to the suction pipe 160 connected to theaccumulator 150 and is used to feed refrigerant gas into the compressionchamber 360, and at the other side thereof with a discharge port (notshown) to guide the refrigerant gas compressed in the compressionchamber 360 to the outside of the compression chamber 360.

The upper bearing 340 has a discharge hole 380 formed in communicationwith the discharge port (not shown) in order to discharge therefrigerant gas guided through the discharge port (not shown) to theoutside. A valve device 390 is arranged on the upper bearing 340 at aposition immediately above the discharge hole 380 and is used to open orclose the discharge hole 380. A mixture of refrigerant and oil isintroduced through the suction port 370 and is supplied into thecompression chamber 360. Of the mixture, the oil serves to seal theinterior of the compression chamber 360. The amount of oil supplied intothe compression chamber 360 may be determined to assure appropriatemixing with the refrigerant within a range exerting no degradation incompression efficiency.

FIG. 3 is a sectional view illustrating the compressing device and thelower cap of the rotary compressor according to the embodiment, and FIG.4 is an enlarged perspective view of the lower bearing and the lower capaccording to the embodiment.

As shown in FIGS. 3 and 4, in the rotary compressor 10 according to theembodiment, the compressing device 300 and the lower cap 130 arearranged close to each other, such that a weld zone 400 is created at acontact position therebetween. The weld zone 400 may be created in aboundary region between a reinforcing protrusion 353 extending from thecompressing device 300 to the lower cap 130 and a through-hole 130 a ofthe lower cap 130.

The lower bearing 350 of the compressing device 300 includes a bearingbody 351 in close contact with the lower surface of the cylinder 330, arotating shaft inserting portion 352 located at the center of thebearing body 351 and extending perpendicular to the bearing body 351,through which the rotating shaft 230 is inserted, and at least onereinforcing protrusion 353 extending in an axial direction A of thebearing body 351.

The lower cap 130 includes a bottom portion 131 arranged to close thelower end opening of the case 100, and a peripheral portion 132extending upward from a peripheral edge of the bottom portion 131. Theboundary region between the peripheral portion 132 of the lower cap 130and the case 100 is subjected to welding in the peripheral direction, tocreate the fixing weld zone 140 for fixedly welding the lower cap 130 tothe case 100.

Also, the weld zone 400 is created in the bottom portion 131 via thethrough-hole 130 a, i.e. in the boundary region between the through-hole130 a and the lower bearing 350, thereby fixedly welding the lowerbearing 350 to the lower cap 130. In this way, the compressing device300 is fixedly welded to the lower cap 130 located therebelow to therebybe fixed inside the case 100. More particularly, as the cylinder 330 isfixedly welded in the axial direction A to the lower cap 130 via thelower bearing 350 that supports the cylinder 300, the cylinder 330 maybe fixed inside the case 100 without unwanted movement:

The reinforcing protrusion 353 extends downward from the lower bearing350 in the axial direction A, to allow the lower bearing 350 to bewelded to the lower cap 130. In the embodiment as shown in FIG. 2, threecylindrical reinforcing protrusions 353 may be arranged on peripheralpositions of a lower surface of the bearing body 351 to extend parallelto the rotating shaft inserting portion 352 in the axial direction A. Ofcourse, the reinforcing protrusions 353 are simply provided for thepurpose of connecting the compressing device 300 to the lower cap 130for welding therebetween and therefore, the reinforcing protrusions 353may be replaced by various numbers and shapes of substitutions betweenthe lower bearing 350 and the lower cap 130.

Now, an assembly method of the rotary compressor according to theembodiment will be described.

First, the stator 210 of the drive device 200, the compressing device300, and the rotor 220 of the drive device 200 are sequentiallypress-fitted into the case 100. Then, in a state wherein a gap gauge(not shown) is inserted into a gap between the stator 210 and the rotor220, a height of the rotary compressor 10 is aligned.

Next, the peripheral portion 132 of the lower cap 130 is inserted intothe lower end opening of the case 100 and is fixedly welded to the case100. Then, the bottom portion 131 of the lower cap 130 is welded to thecompressing device 300 in the axial direction A, to fix the compressingdevice 300 inside the case 100.

After removing the gap gauge (not shown) between the stator 210 and therotor 220, the upper cap 120 is welded to the case 100, completing theassembly of the rotary compressor 10.

Hereinafter, operation of the rotary compressor according to theembodiment will be described.

In the rotary compressor 10 according to the embodiment, to fix thecompressing device 300 inside the case 100, the compressing device 300is welded in the axial direction A of the case 100, rather than beingwelded in a radial direction of the case 100. Therefore, interiorelements, such as, e.g., the cylinder 330 and the rotating shaft 230,may be fixed at positions assuring smooth motions thereof.

Further, owing to the weld zone 400 for fixation of the compressingdevice 300 being provided in the boundary region between the compressingdevice 300 and the lower cap 130, neither the cylinder 330 nor the upperbearing 340 are thermally deformed by heat generated during welding.

Furthermore, in a state wherein the gap gauge (not shown) is insertedbetween the stator 210 and the rotor 220 of the drive device 200 toassure a desired space, the lower cap 130 is first welded to the case100 and thereafter, is welded to the compressing device 300. Thisassures the welding of the compressing device 300 to have only minimaleffect on a gap of the rotary compressor 10, preventing deterioration inperformance of the rotary compressor 10 caused when the stator 210 androtor 220 of the rotary compressor 10 are incorrectly aligned.

Next, another embodiment will be described with reference to FIGS. 5 and6. The same or similar elements as those of the previous embodiment aredenoted by the same reference numerals, and a description thereof willbe omitted. FIG. 5 is a sectional view illustrating a rotary compressoraccording to another embodiment, and FIG. 6 is an enlarged perspectiveview illustrating a lower cap of the rotary compressor shown in FIG. 5.

A rotary compressor 10′ according to the present embodiment includes thecase 100 defining an external appearance of the compressor 10′, acompressing device 300′ arranged inside the case 100, a lower cap 130′coupled to the lower end opening of the case 100, and a weld zone 400′to fix the compressing device 300 and lower cap 130′ to each other.

The weld zone 400′ according to the present embodiment may be created ina boundary region between a supporting protrusion 133′ extending fromthe lower cap 130′ to the compressing device 300′ and the compressingdevice 300′.

The lower cap 130′ includes a bottom portion 131′ arranged to close thelower end opening of the case 100, and a peripheral portion 132′extending upward from a peripheral edge of the bottom portion 131′. Atleast one supporting protrusion 133′ may protrude upward from the bottomportion 131′ and in turn, a through-hole 130 a′ may be perforatedthroughout the supporting protrusion 133′.

A certain number of supporting protrusions 133′ may be arranged onperipheral positions of the bottom portion 131′. Of course, similar tothe above-described reinforcing protrusions 353, the number and shape ofthe supporting protrusions 133′ may be determined in various manners solong as the supporting protrusions 133′ provide satisfactory connectionbetween the compressing device 300′ and the lower cap 130′. That is, theshape and size of the supporting protrusions 133′ may be determined insuch a manner that the supporting protrusions 133′ formed on the bottomportion 131′ come into close contact with the compressing device 300′when the lower cap 130′ is inserted into the lower end opening of thecase 100, thereby being fixedly welded to the compressing device 300′via the through-holes 130 a′.

Accordingly, the compressing device 300′ is fixedly welded to the lowercap 130′ located therebelow to thereby be fixed inside the case 100.More particularly, as the cylinder 330 is fixedly welded in the axialdirection A to the lower cap 130′ via a lower bearing 350′ that supportsthe cylinder 300, the cylinder 330 may be fixed inside the case 100without unwanted movement.

As is apparent from the above description, a rotary compressor accordingto the embodiments is basically configured in such a manner that acompressing device is axially welded to a lower cap, preventing thermaldeformation of interior elements while assuring that the interiorelements are coupled at accurate positions for smooth motion thereof.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A rotary compressor comprising: a case defining an externalappearance of the compressor; a compressing device arranged inside thecase; a lower cap fixed to a lower end of the case; and a weld zone tofix the compressing device and lower cap to each other.
 2. Thecompressor according to claim 1, wherein the weld zone is formed by atleast one reinforcing protrusion extending from the compressing deviceto the lower cap by a predetermined length.
 3. The compressor accordingto claim 1, wherein the weld zone is formed by at least one supportingprotrusion protruding from the lower cap to the compressing device by apredetermined length.
 4. The compressor according to claim 2, whereinthe compressing device includes a cylinder defining a compressionchamber for compression of refrigerant gas, and a lower bearing tosupport the cylinder from the lower side of the cylinder, and whereinthe weld zone is formed in a boundary region between the reinforcingprotrusion axially provided at the lower bearing and a through-holeperforated in the lower cap.
 5. The compressor according to claim 3,wherein the compressing device includes a cylinder defining acompression chamber for compression of refrigerant gas, and a lowerbearing to support the cylinder from the lower side of the cylinder, andwherein the weld zone is formed in a boundary region between athrough-hole perforated in the supporting protrusion and the lowerbearing.
 6. The compressor according to claim 2, wherein the reinforcingprotrusion is provided at a peripheral position of a lower bearing tocome into close contact with a bottom surface of the lower cap when thelower cap is fixed to the case.
 7. The compressor according to claim 3,wherein the supporting protrusion is provided at a peripheral positionof the lower cap to come into close contact with a lower bearing whenthe lower cap is fixed to the case.
 8. The compressor according to claim4 or 5, wherein the compressing device further includes an upper bearingto support the cylinder from the upper side of the cylinder.
 9. Thecompressor according to claim 8, further comprising: a stator fixed tothe case; a rotor rotatably supported inside the stator; and a rotatingshaft press-fitted in the rotor.
 10. A rotary compressor comprising: acase; a cylinder arranged inside the case; a lower bearing closelycoupled to a lower end of the cylinder; and a lower cap fixedly weldedto the lower bearing for fixing the cylinder in an axial direction. 11.The compressor according to claim 10, wherein at least one protrusion isprovided between the lower bearing and the lower cap, to fixedly weldthe lower bearing to the lower cap.
 12. The compressor according toclaim 10, wherein the protrusion is integrally formed with any one ofthe lower bearing and the lower cap.